Process of producing low-carbon ferro alloys.



No. 825,348. PATENTBD JULY10, 1906. E. P. PRICE.

PROCESS OF PRODUCING LOW CARBON PBRRO ALLOYS.

APPLIOATIOK FILED NOV; 14. 19 05."

771 66166366: Jnveyrzor:

- g WM and very low in" carbon.

STATES PATENT @IFIF EDGAR r. PRICE, or NIAGARA FALLS, new roan.-

PROCESS P PRODUCING LOW CARBQN FERRU strove.

1 Specification of Letters Patent.

Patented Jur 10, 1906.

Application filed November 14,1905. Serial No. 287.356.

T9 (ZZZ-whom it. may concern: I

Be it known that I, EDGAR Fl PRI E, a citizen of the United'States,residing at Niagara Falls, in the county of Niagara and State of similaralloys, and contemplatesthe use of ferrosilicon as a-reducing agent. Itis possible to electrically roduce this silicid with a silicon contentof fifty per cent. and upward According to the present invention theproduction of low-car bon fer'ro alloys is effected by a continuousoperation comprising twostages. In the 3, if used, and the chargeforexample, a

first stage ferrosilicon high in silicon and low in carbon is producedby electrically smelting a charge of silica, iron ore, or iron andcarbon. The molten silicid is tapped from the smelting-furnace andallowed to solidify. The ingot is then broken into fragments, which aremixed with a granular body of the compound to be reduced.for example,chromiteand the mixture is smelted in an electric-arc furnace. A basicflux, such as lime, isp'referably mixed with the charge to convert thesilica produced by the reduction of oxid ores into a fusible slag.

,Suitable apparatus for carrying out the process is shown in theaccompanying drawings, in which Figure 1 is an axial section of'thefurnace for producing the ferrosilicon, and 2 is an axial section of thearc-furnace-for utilizing the ferrosilicon to effect reduction.

The smelting-furnace 1 shown in Fig. 1 comprises a body 2 of fire-brickor magnesia, with a lining 3 of refractory material, such ascarborundum, siloxicon, silica, or carbon. Tap-holes 4 5 for slag andmetal extend through the side walls at different heights. Carbonelectrodes 6 7 of opposite polarity depend into the furnace. Inemploying this furnace tocarry out the first stage of the process an arcis established between theele'ctrodes or between each electrode and thecarbon lining mixture of finely-ground silica, iron ore, and

. coke, the silica and carbon preferably being in relatively largeamountis fed in. As'reductlon progresses the slag is withdrawn atintervals through the tap-hole 4, and the al-,

loy is intermittently tapped into a castingpot 9, and more of the chargemixture is fed into the furnace as required.

In the second stage of the process the cast ingot of ferrosilicon isbroken into pieces, and the fragments are mixed with the ore to bereduced and a flux. The mixture is then charged'into the furnace shownin Fig. 2. This furnace has a body 10 of refractory material, such aschromite or magnesia, and a hearth 11 of carbon, surrounded by a metalcasing 12, having an electric terminal 13. The'carbon hearth constitutesone electrode, and the other electrode is a depending carbon rod 14.Tap-holes 15 16 for slag and metal extend through the side walls atdifferent heights.

In employing this furnace to carry out the second stage of the processan arc is estab lished between the depending electrode and the carbonhearth, and a small amount of the chargefor exam lo, a mixture ofchromite, ferrosilicon, an lime'is fed in. The furnace is then graduallyfilled until in its normal working condition the depending electrode isembedded in the charge, as illustrated. .Asthe iron and chromium arereduced a layerof moltenferrochromium collects in, the bottom of thefurnace and maybe removed from time to time through the taphole 16. Whena considerable layer of slag collects upon the metal, it may be removedthrough the tap-hole 15. It will be seen that the deep body of thecharge surrounding the depending electrode effectively protects it fromoxidation and retains the heat within the furnace, both increasing theproduction of metal andmaintaining the slag in a molten conditionWithout especial atten tion. The use of this deep body is madepossibleby, and makes it important to employ,

the minimum potential difference between the electrode-terminals toprevent excessive waste of current by-shunting. through the charge. Thefurnace is operated continuously, the metal and slag being drawn off andthe charge mixtureaddedas required. A clean separation between the metaland slag is usually effected by'tapping them out at difierent levels andalways leavinga certain amount of each within the furnace. The secondstageof the process may obviously be carriedout in a furnace having twodepend ing electrodes of opposite polarity.

. This process enables a ferro alloy containing a minimum orpredetermined lowper centage of carbon to .be continuously produced j 5quired at relatively low cost, the use of charge l tentialdiflerencerequisite to efi'ect reduction,

containing a large percentage of silica and. thereby substantiallypreventing loss oi eleccarbon producing'a'silicid low in carbon andserving as an effective reducing agent. i 5 a I claim- 7 1. The processof producing low-carbon ierro alloys, which consists in providing acharge containing ferrosilicon and a comcharge containing ferrosih'con,an oxidized pound of a metal reducible by silicon and alre loyable withiron,establishing anelectric arc within the charge, surrounding the,zone of reduction and protecting the electrodes from the oxidizingeiiect of the atmosphere by a considerable body of the charge, tappingthe resulting slag and ferro alloy, from the iu'r nace, and\ supplyingthe charge mixture as required, as set forth. x 1

2. The process of producing low-carbon j l erro alloys, which consistsin providing 'a charge containing ferrosilicon, ,an .oxidized compoundof ametal reducible by silicon and alloyable'with iron, and a basic.flux, establishing an electric are within the charge, surrounding thezone of reduction and pro- 2 5 tecting the electrodes from the oxidizingeffect of the atmosphere by a. considerable .body of the charge, tappingthe resultinslag and ferro alloy from-the furnace, 'an supplying thecharge mixture as required, as 0 set forth.

i 3. The process ferro alloys, which consists in providing a chargecontaining ferrosilicon and a compound ofa metal reducible by siliconand al- 5 loyable with iron, establishing an electricarc the charge,surrounding the zone of reduction and protecting the electrodes'i'romthe oxidizing effect of the atmosphere by a' considerable body of thecharge, tapping the acresulting slagand ferro .alloy .from'the furnaceatdifierent levels, and supplying the .fect of theatmosphere by aconsiderable charge mixture as required, as set forth 7 4. The processof producing low carbon ferro alloys, which consists in providingga 5charge containing ferrosilicon, an oxidized compound of a metalreducibleiby silicon and alloyable'with iron, andah'ashrfiux,establishing an electricare within" the charge, -sur-" rounding the zoneofreduction; and protect 'f 5o ing the electrodes from the oxidizingeiiect ofthe atmosphere by a considerable body crate charge, tapping theresulting slag and term alloy from the furnace at difierent. levels, andsu plying the charge mixture as re- ,as set forth. V r 5. The processof. produtninglOW-carbon 'ferro alloys, which consists'in-providing acharge containing ferrosilicon and acompound of a metal'reducible bysilicon and al- 6o loyable with iron,'establishing an electric arewithin the charge, surr0unding the zone of reductionandgprotectin theelectrodes from the oxidizing effect oft e atmosphere by a considerablebody of the charge, maintain-.

6; ing between the electrodes the minimum poof'producing low-carbon vtric current by leakage through the charge, separately tapping theresulting slag and ierro alloy from the furnace, and supplying thecharge mixture asrequired, as set forth.

6. The process of producing low-carbon terro alloys, which consists inproviding a compound of a metal reducible by silicon and alloyable withiron, and a basic flux, establishing an electric arc within the charge,sur rounding the zoneof reduction and protecting the electrodes from theoxidizing effect of the atmosphere by a considerable body of the charge,maintaining between the electrodes the minimum potential differencerequisite to eilect reduction, thereby substantially preventing loss ofelectric current by leakage through the charge, separately tapping theresulting slag and ferro alloy from theiurnace, and supplying the chargemixture as required, as set forth.

.7. The process of producing low-carbon ferrochromium, which consists inproviding a charge containing ferrosilicon and a com pound of chromium,establishing an electric ,arc within the charge, surrounding the zoneof-reduction and protecting the electrodes irom the oxidizingefiect'ofthe atmosphere by a considerable body of the charge, tappingthe resulting slag and ferro alloy from the furnace, and supplying thecharge mixture as required, as set forth.

8. The process of producing low-carbon ferrochromium, wh ch consists inprovidin a charge containing ferrosilicon, an oxidize compound ofchromium, and a basic flux, establishing an electric are within thecharge, surrounding the zone of-reduction and protecting the electrodesfrom the oxidizing cf body of the charge, tapping the resulting slag andierro alloy from thefurnace, and supplying the charge mixture asrequired, as set .forth.

9. The .process of producing low-carbon ferrochromium, which consistsihproviding a chargecontaining ferrosihcon and a compound of chromium,establish ng an electric "are within" the charge, surrounding the zoneof reduction and protecting the electrodes from the oxidizing effect ofthe atmosphere by a considerable'body of the charge, tapping theresulting slag and ferro alloy from the furnace at different levels, andsupplying the charge mixture as required, as set forth. 10. The processof producing low-carbon ferrochromium, which consists in providing.

a charge containing ferrosilicon, an oxidized compound of,chromium,'anda basic flux, es-- tablishing anelectric-arc within the charge,surrounding the zone of reduction and protecting the electrodes from theoxidizing effect of the atmosphere by a considerable body of the poundof chromium,

charge, tapping the resulting slag and ferro alloy from the furnace atdifferent levels, and supplying the charge mixture as required, as setforth. a

p 11. The process of ferrochromium, which consists in providing a chargecontaining ferrosilicon and a compotentialdiflerence requisite to effectreduction, thereby substantially preventing loss of electric current byleakage through the charge, separately tapping the resulting slag andferro alloy from the furnace, and supplyingthe charge IniXture'asrequired, as set forth.

12. The processof producing low-carbonproducing lOW,- carbonestablishing an electric are within the charge, surrounding'the zone Iferro chromium, which consists in providing a charge containingferrosihcon, an oxidized compound of chromium, and a basic flux, es-

tablishing an electric are within the charge, surrounding the zone ofreduction and protec ting the electrodes from the oxidizing effect ofthe atmosphere byaconsiderable body of the charge, maintaining betweenthe electrodes the minimum potential dillerence'requisite to effectreduction, ther'eb r substantially preventing loss of electric currentby leakage through the charge, separately tapping the resulting slag andferro alloy from the furnace, and supplying the required, as set forth.-Y

In testimony whereof I aflix my signature in presence of two Witnesses.

w EDGAR FJPRICE. Witnesses:

G. E. Cox, D. BURGESS.

charge mixture as"

